Many women in the western world faces the prospect of breast cancer and when it comes to tumour therapy it is important that a high quality diagnosis of the tumour is made. The diagnosis is often based on morphological findings and there are today two main methods for morphological diagnosis of breast lesions i.e. histopathological examination of surgical or punch biopsies and cytopathological examination of fine needle aspirates.
In punch or core biopsy, a tissue sample of the lesion is removed, for instance with the use of a coarse punching biopsy-needle, which sample is subsequently examined histologically. This procedure is generally associated with side-effects e.g. extensive local bleeding and pain. The total expenses for each diagnosed lesion are high in comparison with the cost associated with the corresponding cytological diagnosis.
With cytological diagnosis, single cells and small cells complexes are aspirated from the lesion with the aid of a fine needle in which low pressure is created during the sampling process. Due to the lower adhesion between tumour cells than between healthy cells, the tumour cell concentration in the sample is enriched. Subsequent to taking the cell sample, the cell material is examined by e.g. ejecting them onto a glass slide, where they are smeared, fixed, stained and examined cytomorphologically. Ongoing advances in genetics and functional genomics suggest that a completely objective molecular diagnostic procedure in single cells from fine needle aspirates will be available in a near future.
In the recent years it has been possible to detect smaller and smaller tumours, for instance through the technical development of screening mammography and ultrasound diagnostic scanning. It is not unusual to detect tumours which are in the size of just a few millimetres. Especially these small tumours but also tumours of sizes 10-20 mm in diameter are frequently non-palpable and undergo anatomical distortion when hit by the needle. The reason is that the glandular breast tissue is surrounded by a loose fatty and connective tissue, which makes it difficult to correctly position and move the needle into the tumour and the problem aggravates if the tumour is hard or fibrous, which is most often the case. Thus, the insertion of above all core biopsy needles but also fine needles into the tumour is often difficult or even impossible.
From U.S. Pat. No. 4,605,011 (J. NÄSLUND) it is known to take samples of cells from small tumours with the aid of a fine-needle puncturing technique. The patent specification describes a cell sampling apparatus with a removable connected syringe provided with a cannula which can be driven with an oscillating, reciprocatory movement into the tumour in order to facilitate the insertion of the cannula into said tumour. Said apparatus is provided with means for creating reduced pressure in the cannula for driving a cell sample thereinto.
Cell sampling from tumours of small sizes (2-10 mm in diameter) is frequently associated with major sampling problems resulting in non-representative or sparse cellular material. This is a decisive drawback of this patient-friendly method because of the rapid increase of the total number of breast tumours below the size of 10 mm detected by means of mammography and ultrasound screening.
WO 00/56208 describes a fine needle biopsy device for extracting tissue from the body predominantly in suspected cases of breast cancer. The device causes a fine needle, which is attached to the device to reciprocate and/or rotate at the same time causing tissue to enter the needle, optionally with the aid of suction for aspiration of the tissue sample. The frequency used for the reciprocating movement is in the range of 10-20 Hz and moreover, the reciprocating and the rotational movement, respectively, may not be changed independently.
The fact that the adhesion between tumour cells is less than between healthy cells, causes another problem with the cytological aspiration technique. The insertion of the needle into the tumour, followed by the withdrawal of the “contaminated” needle is believed to cause a certain risk of tumour cells to spread in the needle channel, which might give rise to a local spread of tumour cells (seeding).
Another issue in the cytological aspiration technique to attend is the prevention of filling the needle with material from tissue surrounding the tumour when the needle is inserted into the breast.
Still another issue to attend is the cell sampling of cystic tumours. If a lesion is cystic, the obtained sample volume is increased. However, the cell material in the sample will be diluted. At the present the sample may for instance undergo centrifugation subsequent to the sampling procedure in order to retrieve the cells to be examined cytomorphologically. This is a rather labour intensive and time consuming procedure and often the retrieved cell concentration is low.
The cytological aspiration technique for diagnosis of tumours is however a very promising technique since the side effects are lenient and few, especially when objective molecular diagnostic methods will be available. For instance, the technique does not cause any severe internal bleeding or major pain, thus providing a great benefit for the patient and in the end lowered costs for the society. Moreover, cytological aspiration is also associated with a relatively low success rate for physicians without considerable experience. Consequently, there is a need for standardisation and improvements of said technique, such as in a standardised way providing a good penetration and low anatomical distortion of small tumours, in the meantime yielding an increase of the amount of cells in the sample taken to ensure a high quality diagnosis. There is also a need for a lowering of the risk for the tumour to spread when a cell sample is taken from a tumour, for instance a histologically poorly differentiated highly malignant tumour.
Further there is a need for an arrangement that in an effective way prevents the needle to be filled with unwanted material during the insertion of the needle into the breast and into the tumour. Moreover, there is a need for an arrangement that in an effective way increases the cell concentration when taking a cell sample from for instance a cystic tumour, which also provides for a faster and less labour intensive procedure.